Construction of Enantioselective Photochromic System Controlled by Chirality of the Reaction-Field

DNA-季铵离子配合物（DNA- qaic）是通过在DNA上添加二甲二十二胺盐而得到的。阐明了DNA-QAIC可以作为光致变色反应的透明基质。含二亚乙烯的dna -季铵离子络合物（DNA-QAIC）拉伸膜通过其光致变色反应表现出较大的可逆旋光度变化。二芳乙烯在溶液中表现出与有色形式相似的转化率，而不管其结构中羟基的存在与否。二亚乙烯在有DNA-QAIC存在的DNA-QAIC薄膜或有机溶剂（如氯仿）中的反应活性低于无DNA-QAIC的溶液。在苯并噻吩环上2位有羟基的二乙烯即1,2-二（2-羟甲基-3-苯并噻吩基）六氟环戊烯与DNA-QAIC一起溶解在氯仿中不显色。这是因为二乙烯的构象被固定在一个不可环化的平行构象上。结果表明，二乙烯分子部分插入DNA碱基对之间。众所周知，氨基蒽可以插入DNA碱基对之间。含氨基蒽的二乙烯嵌在溶液中DNA碱基对之间的蒽部分。结果，虽然观察到光致变色反应，但荧光性质有一定程度的改变。虽然螺吡喃粉末未检测到光致变色反应，但含有螺吡喃的DNA-QAIC粉末表现出热可逆的光致变色反应。在这种情况下，认为粉末中的螺吡喃嵌入DNA-QAIC中，DNA-QAIC可以作为光致变色反应的透明基质。螺旋吡喃在DNA-QAIC膜中的热脱色反应较慢，光-热稳态吸光度小于聚苯乙烯膜。在DNA-QAIC薄膜中掺杂的螺吡喃类化合物的结构和运动受到限制，难以转变为相应的merocyanine形式。少

DNA- quaternary ammonium ion complex(DNA-QAIC) was obtained by the addition of dimethyldioctadecylammoniun salt to DNA, according to the procedures previously reported. We have clarified that DNA-QAIC can be the transparent matrices of photochromic reactions.The stretched films of DNA-quaternary ammonium ion complex (DNA-QAIC) incorporating diarylethene exhibited large reversible change in optical rotation by its photochromic reactions.Diarylethenes show similar conversion ratio to their colored form in solution, regardless of the presence or absence of the hydroxyl groups in their structure. The diarylethenes showed lower reactivity in DNA-QAIC film or in organic solvents like chloroform in the presence of DNA-QAIC, than in solution without DNA-QAIC. The diarylethene with hydroxyl groups at 2-positions of the benzothiophene rings, that is 1,2-bis(2-hydroxymethyl-3-benzothienyl)hexafluorocyclopentene, showed no coloration when it is dissolved in chloroform together with DNA-QAIC. It is … More because the conformation of the diarylethene was fixed to a non-cyclizable parallel conformation. It was suggested that the diarylethene molecules were partly intercalated between the DNA base pairs.It is well-known that amioanthracene can intercalate between DNA base pairs. The diarylethene with an aminoanthracene intercalated at the anthracene moiety between the DNA base pairs in solution. As the result, fluorescence property changed to some extent, although the photochromic reaction was observed.Although the photochromic reaction were not detected for the powder of spiropyran, the powder of DNA-QAIC incorporating spiropyran showed thermally reversible photochrimism. In this case, the spiropyran in the powder were considered to be intercalating into the DNA-QAIC, and DNA-QAIC can be the transparent matrices of photochromic reactions. The thermal decoloration reactions of spiropyrans in DNA-QAIC films was slower, and the absorbance at the photo-thermo-stationary state was smaller than those in polystyrene films. The structure and the motion of spiropyrans doped in the DNA-QAIC films were restricted, so that it was difficult to change to the corresponding merocyanine form. Less